Kadanoff-Baym approach to double-excitations in finite systems
Abstract
We benchmark many-body perturbation theory by studying neutral, as well as non-neutral, excitations of finite lattice systems. The neutral excitation spectra are obtained by time-propagating the Kadanoff-Baym equations in the Hartree-Fock and second Born approximations. Our method is equivalent to solving the Bethe-Salpeter equation with a high-level kernel while respecting self-consistently, which guarantees the fulfillment of a frequency sum rule. As a result, we find that a time-local method, such as Hartree-Fock, can give incomplete spectra, while already the second Born, which is the simplest time-nonlocal approximation, reproduces well most of the additional excitations, which are characterized as double-excitations.
Keywords
Cite
@article{arxiv.1108.4106,
title = {Kadanoff-Baym approach to double-excitations in finite systems},
author = {N. Säkkinen and M. Manninen and R. van Leeuwen},
journal= {arXiv preprint arXiv:1108.4106},
year = {2012}
}
Comments
20 pages, 10 figures